Resin composition for toner and toner

ABSTRACT

A resin composition for toners which comprises: (A) a wax composition comprising an ethylene polymer having a melt index of from 0.1 to 100 as measured at 190±0.4° C. and a paraffin wax having a melting point of from 70° C. to 120° C. or a Fisher-Tropsch wax having a melting point of from 70° C. to 120° C.; and (B) a binder resin for toners.

TECHNICAL FIELD

The present invention relates to a resin composition for toners used forelectrophotographs and the like, and a toner.

BACKGROUND ART

Electrophotography in copiers and printers generally uses a process thatincludes electrostatically forming a latent image on a photosensitivematerial, developing the latent image by use of a toner, transferringthe toner image on a sheet to be fixed, such as a piece of paper, andsubsequently pressure fixing the image by a heat roller (the heatroller-fixing process). This heat roller fixing process requires a tonerwith good fixation properties, which permits fixation at lowertemperature, for the improvement of cost efficiency in power consumptionand the like, the increase of copying speed, and the prevention ofcurling of a sheet and the like. In addition, needs for a high qualityimage and high resolution of a copy image have recently been growing asa result of the development of computers, high resolution TV's, or thelike.

In response to such demands, the proposals of the prior art include aproduct in which the molecular weight and molecular weight distributionof the binder resin are improved. The fixing temperature can be loweredby making low the molecular weight of the binder resin to therebydecrease the melt viscosity thereof. However, lowering the molecularweight decreases the melt viscosity, which simultaneously decreases thecohesive strength of the resin, leading to the problem of causing atoner offset to the fixing roll.

In order to prevent such a problem, a material of a wide moleculardistribution, made by mixing a resin of a high molecular weight and aresin of a low molecular weight, is utilized as the binder resin andfurther the high molecular weight portion of a binder resin is madecross-linked. However, this method increases the viscosity of the resinand thus, on the contrary, makes it difficult to satisfy the fixationproperties.

In addition, in order to acquire sufficient fixation properties, amethod of decreasing the glass transition temperature of the resin isknown; however, in this case, loss of preserving properties of the toneris unavoidable.

Further, in order to impart offset resistance, a method is known inwhich a polypropylene wax is made contained as a releasing agent.However, the melting point of polypropylene is generally as slightlyhigh as from 130 to 150° C., which causes the problem of not showing itseffect at a low fixing temperature.

Furthermore, a method in which a Fischer-Tropsch wax or amicrocrystalline wax is made contained as a releasing agent is known inU.S. Pat. Nos. 5,629,122, 5,547,799, 5,702,859 and 5,780,197, etc. Thesewaxes have melting points lower than that of a polypropylene wax, and sothey are thought to show releasing agent effects even at lowertemperatures. However, even these methods are not sufficient in hotoffset properties and thus improvement is required.

So far, a variety of methods were attempted; however, a method in whichparticularly the aforementioned problems are solved has not providedyet.

DISCLOSURE OF THE INVENTION

The present invention can solve the aforementioned problems of theconventional toners and its object is to provide a resin composition fortoners and a toner, excellent in low temperature fixation, offsetresistance and preserving properties.

The inventors carried out investigations in order to solve theaforementioned problems; as a result, they have made the inventionsdescribed below.

[1] A resin composition for toners comprising:

(A) a wax composition comprising an ethylene polymer having a melt indexvalue of from 0.1 to 100 as measured at 190±0.4° C. and a paraffin waxhaving a melting point of from 70° C. to 120° C. or a Fisher-Tropsch waxhaving a melting point of from 70° C. to 120° C.; and

(B) a binder resin for toners.

[2] The resin composition for toners according to [1], in which

with respect to a whole resin composition for toners, a content of the(A) component is from 0.05% by weight to 15.0% by weight, and a contentof the (B) component is from 85.0% by weight to 99.95% by weight; and

with respect to a whole (A) component, a content of the ethylene polymeris from 0.01% by weight to 5.0% by weight, and a total content of theparaffin wax and the Fisher-Tropsch wax is from 95.0% by weight to99.99% by weight.

[3] The resin composition for toners according to [1] or [2], in which

the aforementioned binder resin for toners is a styrene polymer(copolymer).

[4] The resin composition for toners according to [3], in which

the aforementioned styrene polymer (copolymer) contains a constituentderived from a styrene monomer and a constituent derived from a(meth)acrylate monomer or a (meth)acrylic acid monomer;

the styrene polymer (copolymer) has a glass transition temperature Tg offrom 45° C. to 75° C.; and

in a chromatogram as measured by GPC, the styrene polymer (copolymer)has an weight-average molecular weight (Mw) of 100,000 or higher, has atleast one maximum value or one shoulder in both a molecular weight rangeof from 3,000 to 12,000 and a molecular weight range of 100,000 orhigher, and has a ratio (Mw/Mn) of Mw to number average molecular weight(Mn) of from 15 to 100.

[5] The resin composition for toners according to [1] or [2], in which

the aforementioned binder resin for toners is a polyester copolymer.

[6] The resin composition for toners according to [5], in which

the aforementioned polyester copolymer has a glass transitiontemperature Tg of from 45° C. to 75° C.; and

in a chromatogram as measured by GPC, the polyester copolymer has an Mwof from 6,000 to 150,000, has at least one maximum valve or one shoulderin the molecular weight range of from 3,000 to 12,000, and has an Mw/Mnof 5 or more.

[7] The resin composition for toners according to any of [1] to [6], inwhich

the resin composition for toners further includes a polyolefin wax.

[8] A toner comprising the resin composition for toners according to any[1] to [7].

The wax composition of the present invention is a mixture containing anethylene polymer composed of an ethylene monomer as a primaryconstituent and a paraffin wax or a Fisher-Tropsch wax and preferablyfurther containing a polyethylene wax.

Inclusion of an ethylene polymer composed of an ethylene monomer as theprimary constituent in the wax composition allows good dispersion of aparaffin wax or a Fisher-Tropsch wax into the binder resin. This permitsthe appearance of good fixation and good offset performance. Inclusionof a polyethylene wax is more preferable for better wax dispersion.

A resin composition for toners and a toner of the present invention aremade composed as described above and are excellent in offset resistance,fixation and preserving properties.

As a consequence, a resin composition for toners and a toner of thepresent invention can sufficiently meet recent increasing demands suchas speedup of copying, energy conservation and high image quality.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be described in detail.

(Wax)

A paraffin wax of the present invention refers to a mixture ofhydrocarbons whose main component is normal paraffin, a mixture that isextracted, separated and highly refined by operation includingreduced-pressure distillation of petroleum.

A Fisher-Tropsch wax of the present invention refers to a synthesizedwax composed mainly of linear hydrocarbons, which are obtained by, forexample, causing water gas, of which main components are carbon monoxideand hydrogen, to react using a catalyst such as cobalt, nickel or aniron-based material at normal pressure at 170 to 250° C. ThisFisher-Tropsch wax can be synthesized by means of the Fisher-Tropschprocess for utilization or a commercially available one can be utilized.

In the present invention, the melting points of both the paraffin waxand the Fisher-Tropsch wax range from 70° C. to 120° C. If the meltingpoint is too low, the preserving properties of the toner aredeteriorated in some cases. On the other hand, too high meltingtemperature sometimes reduces the fixation of a toner at lowtemperature.

A resin composition for toners of the present invention may containpolyolefin waxes such as a polyethylene wax and a polypropylene wax.Doing this can improve the dispersion of a wax in a toner. The amount ofaddition is preferably in the range of from 0 to 10% by weight withrespect to the total amount of the resin compositions for toners.

Polyolefin waxes normally have a high viscosity as compared withparaffin waxes and Fisher-Tropsch waxes. When a polyethylene wax, forexample, is used as a polyolefin wax, a wax with a melting point of 90to 130° C. as measured by a DSC method is preferable. In addition,preferably, the viscosity-average molecular weight is less than 8,000and the crystallinity index is 60% or more. The dispersion of a wax in atoner can be improved by containing in the wax composition apolyethylene wax that satisfies the aforementioned physical properties.

Illustrative examples of trade names corresponding to the aforementionedpolyolefin waxes include Hi-waxes 800P, 400P, 200P, 100P, 720P, 420P,320P, 405MP, 320MP, 4051E, 2203A, 1140H, NL800, NP055, NP105, NP505 andNP805, commercially available from Mitsui Chemicals Inc.; however, thepolyolefin waxes are not limited to these products.

Further, the resin compositions for toners of the present invention mayinclude natural waxes such as ceramic wax, rice wax, sugar wax, urushiwax, beeswax, carnauba wax, candelilla wax and montan wax, and theamounts of addition thereof preferably range from 0 to 10% by weightbased on the weight of resin composition for toners.

(Ethylene Polymer)

Ethylene polymers of the present invention contain a unit derived fromethylene monomer as the primary constituent. Ethylene polymerspreferably contain 90% by weight or more of ethylene monomer. Othermonomers constituting the ethylene polymer are preferably alkylenemonomers such as propylene, butene, pentene and hexene.

The aforementioned ethylene polymers have a melt index value, asmeasured at 190±0.4° C. by exerting a load of 2160±10 g based on JIS K6760, ranging from 0.1 to 100, preferably ranging from 2 to 80. If themelt index value is too low, good fixation performance cannot beobtained in some cases. A too large melt index value does not exhibitgood dispersion of the wax in some cases.

Illustrative examples of trade names of the aforementioned ethylenepolymers include, for example, Mirason Series available from MitsuiChemicals Inc.; however, the ethylene polymers are not limited to theseproducts.

The method of manufacturing a wax composition of the present inventioncomprises feeding a paraffin wax or a Fisher-Tropsch wax and an ethylenepolymer composed of ethylene monomer as the primary constituent inspecified amounts thereof together with a small amount of a solvent intoa mixing vessel and subjecting the mixture to heating, mixing andagitating to thereby mix the mixture uniformly.

(Binder Resin for Toners)

Binder resins for toners in the present invention have the role ofbinding the components of the resin composition for toners and arepreferably styrene polymers (copolymers), polyester copolymers, or thelike for utilization.

(Styrene Polymer (Copolymer))

A styrene polymer (copolymer) used in the present invention includesstyrene monomer as the primary constituent; in which the styrene polymer(copolymer) preferably contains a constituent derived from styrenemonomer and a (meth)acrylate monomer or a (meth)acrylic acid monomer; inwhich the glass transition temperature (Tg) of the styrene polymer(copolymer) is preferably from 45° C. to 75° C.; and in which in achromatogram as measured by GPC, the styrene polymer (copolymer)preferably has an weight-average molecular weight (Mw) of 100,000 orhigher, preferably has at least one maximum value or one shoulder inboth the molecular weight range of from 3,000 to 12,000 and themolecular weight range of 100,000 or higher, and preferably has a ratio(Mw/Mn) of Mw to number average molecular weight (Mn) of from 15 to 100.

Illustrative examples of monomers constituting styrene polymers(copolymers) are indicated below; however, the monomers are not limitedto these.

Styrene monomers include, for example, styrene, α-methylstyrene,halogenated styrene, vinyltoluene, 4-sulfonamide styrene and 4-styrenesulfonic acid.

(Meth)acrylate monomers include, for example, methyl (meth)acrylate,ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate,isobutyl (meth)acrylate, octyl (meth)acrylate, dodecyl (meth)acrylate,lauryl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl(meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, furfuryl(meth)acrylate, hydroxyethyl (meth)acrylate, hydroxybutyl(meth)acrylate, dimethylaminomethyl (meth)acrylate, dimethylaminoethyl(meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-chloroethyl(meth)acrylate.

A styrene polymer (copolymer) preferably contains as monomers from 60 to95% by weight of a styrene monomer and from 5 to 40% by weight of a(meth)acrylate monomer.

Further, illustrative examples of other monomers constituting thestyrene polymer (copolymer) include itaconates, such as dimethylitaconate, dipropyl itaconate, dibutyl itaconate, dioctyl itaconate anddiamyl itaconate, maleates and fumarates, such as maleates and fumarateshaving either linear or branched alkyl groups with the number of carbonatoms of from 1 to 8, diethyl maleate, dipropyl maleate, dibutylmaleate, dipentyl maleate, dihexyl maleate, heptyl maleate, octylmaleate, ethylbutyl maleate, ethyloctyl maleate, butyloctyl maleate,butylhexyl maleate, pentyloctyl maleate, diethyl fumarate, dipropylfumarate, dibutyl fumarate, dipentyl fumarate, dihexyl fumarate, heptylfumarate, octyl fumarate, ethylbutyl fumarate, ethyloctyl fumarate,butyloctyl fumarate, butylhexyl fumarate and pentyloctyl fumarate, andunsaturated carboxylic acids and unsaturated dicarboxylic acids such ascinnamic acid, maleic acid, fumaric acid, itaconic acid and2-vinylnaphthalene, itaconic anhydride, maleic anhydride, acrylamidemethylsulfonic acid, acrylamide ethylsulfonic acid, acrylamiden-propylsulfonic acid, acrylamide isopropylsulfonic acid, acrylamiden-butylsulfonic acid, acrylamide-s-butylsulfonic acid, acrylamidet-butylsulfonic acid, acrylamide pentanesulfonic acid, acrylamidehexanesulfonic acid, acrylatnide heptanesulfonic acid, acrylamideoctanesulfonic acid, methacrylamide methylsulfonic acid, methacrylamideethylsulfonic acid, methacrylamide n-propylsulfonic acid, methacrylamideisopropylsulfonic acid, methacrylamide n-butylsulfonic acid,methacrylamide-s-butylsulfonic acid, methacrylamide t-butylsulfonicacid, methacrylamide pentanesulfonic acid, methacrylamide hexanesulfonicacid, methacrylamide heptanesulfonic acid, methacrylamide octanesulfonicacid, divinylbenzene, 1,3-butyleneglycol diacrylate, 1,5-pentanedioldiacrylate, neopentylglycol diacrylate, 1,6-hexanediol diacrylate,diethyleneglycol diacrylate, triethyleneglycol diacrylate,tetraethyleneglycol diacrylate, polyethyleneglycol diacrylate,polyethyleneglyco #400 diacrylate, polyethyleneglycol #600 diacrylate,polypropylene diacrylate, N,N methylene bisacrylamide, pentaerythritoltriacrylate, trimethylolpropane triacrylate, tetramethylolpropanetriacrylate, 1,4-butanediol diacrylate, diethyleneglycol dimethacrylate,1,3-butyleneglycol dimethacrylate, 1,5-pentanediol dimethacrylate,neopentylglycol dimethacrylate, 1,6-hexanediol dimethacrylate,diethyleneglycol dimethacrylate, triethyleneglycol dimethacrylate,tetraethyleneglycol dimethacrylate, polyethyleneglycol dimethacrylate,polyethyleneglycol #400 dimethacrylate, polyethyleneglycol #600dimethacrylate, polypropylene dimethacrylate, N,N methylenebismethacrylamide, pentaerythritol trimethacrylate, trimethylolpropanetrimethacrylate, tetramethylolpropane trimethacrylate, 1,4-butanedioldimethacrylate and 2,2-bis(4-methacryloxy polyethoxyphenyl) propane.

The styrene polymers (copolymers) can be synthesized by means ofwell-known polymerization processes such as the bulk polymerizationprocess, the solution polymerization process, the suspensionpolymerization process and the emulsion polymerization process.

As polymerization initiators in this case, utilized are, for example,t-butylperoxy methacrylate, t-butylperoxy crotonate, di(t-butylperoxy)fumarate, t-butylperoxy allylcarbonate, tri-t-butyl permellitate,tri-t-amino permellitate, tri-t-hexyl permellitate,tri-t-1,1,3,3-tetramethylbutyl permellitate, tri-t-cumyl permellitate,tri-t-(p-isopropyl)cumyl permellitate, tri-t-butyl pertrimesicite,tri-t-amino pertrimesicite, tri-t-hexyl pertrimesicite,tri-t-1,1,3,3-tetramethylbutyl pertrimesicite, tri-t-cumylpertrimesicite, tri-t-(p-isopropyl)cumyl pertrimesicite,2,2-bis(4,4-di-t-butylperoxycyclohexyl) propane,2,2-bis(4,4-di-t-hexylperoxycyclohexyl) propane,2,2-bis(4,4-di-t-amylperoxycyclohexyl) propane,2,2-bis(4,4-di-t-octylperoxycyclohexyl) propane,2,2-bis(4,4-di-a-cumylperoxycyclohexyl) propane,2,2-bis(4,4-di-t-butylperoxycyclohexyl) butane,2,2-bis(4,4-di-t-octylperoxycyclohexyl) butane.

Preferably, the styrene polymers (copolymers) have an Mw of 100,000 orhigher, have an Mw/Mn of from 15 to 100, and have at least one maximumvalue or one shoulder in both the molecular weight range of from 3,000to 12,000 and the molecular weight range of 100,000 or more, in achromatogram as measured by a GPC. In addition, the Tg of theaforementioned styrene polymers (copolymers) preferably range from 45 to75° C. Satisfying the aforementioned conditions of Mw, Mw/Mn, themaximum value and Tg leads to very good performance in balance offixation, offset and preserving properties.

More specifically, a styrene polymer (copolymer) having an Mw of 100,000or higher, having an Mw/Mn of 15 or more, and having a first maximumvalue or a first shoulder in the molecular weight range of 3,000 to12,000 and a second maximum value or a second shoulder in the molecularweight range of 100,000 or higher, is preferably utilized to therebyenhance the cohesive strength of the styrene polymer (copolymer) leadingto good offset resistance properties. At the same time, a styrenepolymer (copolymer) having an Mw/Mn of less than 100 or having a firstmaximum value or a first shoulder in the molecular weight range of lessthan 12,000 is preferably utilized to thereby decrease the viscosity ofthe styrene polymer (copolymer) leading to good fixation properties. ATg value of 45° C. or higher is preferably to give a good blockingresistance properties and a Tg value of less than 75° C. is preferablyto increase the lowest setting temperature of the toner.

(Polyester Copolymer)

A polyester copolymer used in the present invention is manufactured byutilizing at least one acid component such as terephthalic acid ormalonic acid and at least one alcohol component such as ethylene glycolor butylene glycol and by polycondensating them. In addition, in orderto manufacture a polyester copolymer of a wider molecular weightdistribution, a low molecular weight polyester (a) and a base polyester(b) are prepared in advance and are subsequently mixed and are subjectedto a urethane-producing reaction using a polyisocyanate to obtain aresin as well.

As acid components used for the aforementioned polyester copolymers canbe utilized any acids used when a polyester copolymer is conventionallymanufactured. In addition to the acids indicated above, they include,for example, alkyldicarboxylic acids such as succinic acid, glutaricacid, adipic acid, azelaic acid and sebacic acid, unsaturateddicarboxylic acids such as maleic acid, fumaric acid, citraconic acidand itaconic acid, benzenedicarboxylic acids such as phthalic acid,isophthalic acid and acid anhydrides of these dicarboxylic acids such asphthalic anhydride, and lower alkyl esters. In addition, in order toadjust the molecular weight, monocarboxylic acid and trivalent or morepolycarboxylic acids can also be utilized. Preferable monocarboxylicacids include aliphatic monocarboxylic acids such as octanoic acid,decoic acid, dodecanoic acid, myristic acid, palmitic acid and stearicacid, and may be branched or may have unsaturated groups. Further, thesealiphatic monocarboxylic acids have the characteristic of lowering theglass transition point, and therefore aromatic monocarboxylic acids suchas benzoic acid and naphthalenecarboxylic acid may be used in order tolower the glass transition point. The polycarboxylic acids includetrimellitic acid, pyromellitic acid and the anhydrides thereof.

As for alcohol components, any alcohols can be utilized used when apolyester copolymer is conventionally manufactured. Besides the alcoholsindicated above, they include, for example, alkyldiols such as1,3-butylene glycol, 1,4-butylene glycol, 2,3-butanediol, diethyleneglycol, triethylene glycol, dipropylene glycol, 1,5-pentanediol,1,6-hexanediol, neopentyl glycol and 2-ethyl-1,3-hexanediol, alicyclicdiols such as hydrogenated bisphenol A and cyclohexanedimethanol,derivatives of bisphenol F or bisphenol S, for example the reactionproducts of alkyleneoxides, such as ethylene oxide or propylene oxidewith bisphenol F or bisphenol S, and aromatic diols, such as lower alkyldicarboxylates of bishydroxyethylterephthalic acid,bishydroxypropylterephthalic acid and bishydroxyethylterephthalic acid.Furthermore, bisphenol A derivatives, for example,: alkylene oxideadducts of bisphenol A ,such as, the ethylene oxide adduct of bisphenolA and the propylene oxide adduct of bisphenol A are also included. Inaddition, in order to adjust the molecular weight, monoalcohol andtrivalent and more polyols can be utilized. Preferable monols includealiphatic monoalcohols such as octanol, decanol, dodecanol, myristylalcohol, palmityl alcohol and stearyl alcohol, and may be branched ormay have unsaturated groups. Trivalent and more polyols includeglycerine, 2-methylpropanetriol, trimethylolpropane, trimethylolethane,sorbitol and sorbitan.

The condensation reaction for obtaining the aforementioned polyestercopolymers can be carried out in an inert gas such as nitrogen gas bymeans of a well-known reaction such as solvent-free high-temperaturepolycondensation process or solution polycondensation process. For theuse ratio of carboxylic acid to alcohol for the reaction, the ratio ofthe number of the carboxyl group of the former to that of the hydroxylgroup of the latter generally ranges from 0.7 to 1.4.

In addition, in the polycondensation for obtaining the aforementionedpolyester copolymers, the addition of a catalyst is preferable so as tospeed up the reaction. The aforementioned catalysts include tin-basedcatalysts, more specifically dibutyltin oxide; however, the catalystsare not limited to this species. Further, the amount of addition in thiscase is preferably from 0.01% by weight to 1.00% by weight.

Preferably, the aforementioned polyester copolymers have a glasstransition temperature (Tg) of from 45° C. to 75° C.; in a chromatogramof the copolymers as measured by GPC, the Mw is from 6,000 to 150,000,there is at least one maximum value or one shoulder in the molecularweight range of from 3,000 to 12,000, and the Mw/Mn is 5 or more.Satisfying the aforementioned conditions of Mw, Mw/Mn, the maximum valueand Tg leads to very good performance in balance of fixation, offset andpreserving properties.

More specifically, a polyester copolymer having a Mw of 6,000 or higherand having an Mw/Mn of 5 or more is preferably utilized to therebyenhance the cohesive strength of the copolymer leading to good offsetresistance properties. At the same time, a polyester copolymer having aMw of 150,000 or lower and having at least one maximum value or oneshoulder in the molecular weight range of from 3,000 to 12,000 ispreferably utilized to thereby decrease the viscosity of the polyestercopolymer leading to good fixation properties. A Tg value of 45° C. orhigher is preferably to give a good blocking resistance properties ofthe toner and a Tg value of less than 75° C. is preferably to increasethe lowest setting temperature of the toner.

(Resin Composition for Toners)

In a resin composition for toners of the present invention, with respectto the total resin composition for toners, the content of the waxcomposition, i.e. the (A) component, preferably ranges from 0.05% byweight to 15.0% by weight, more preferably from 0.5% by weight to 10.0%by weight, and the content of the resin, i.e. the (B) component,preferably ranges from 85.0% by weight to 99.95% by weight, morepreferably from 90% by weight to 99.5% by weight.

In addition, with respect to the total (A) component, the content ofethylene polymers is preferably from 0.01% by weight to 5.0% by weight,more preferably 0.1% by weight to 1.0% by weight, and the total contentof paraffin waxes and Fisher-Tropsch waxes is preferably from 95.0% byweight to 99.99% by weight, more preferably 99.0% by weight to 99.9% byweight.

Too low a content of a wax composition does not give sufficient fixationproperties in some cases. On the other hand, if the content of a waxcomposition is too large, sufficient preserving properties cannot beobtained.

Methods of mixing a resin with a wax composition in a resin compositionfor toners of the present invention include (i) a method of dissolving aresin in an organic solvent and mixing a wax composition thereinsimultaneously and (ii) a method of dissolving a wax composition inmonomers to constitute a resin and then polymerizing these monomers.

In addition, to a resin composition for toners of the present invention,besides the aforementioned styrene polymer (copolymer) and polyestercopolymer, may be added a resin such as an epoxy resin, a polyurethaneresin, a polyamide resin or a silicone resin.

(Toner)

A toner of the present invention includes at least a resin compositionfor toners, a charge control agent (CCA), a colorant, and a surfacetreatment, of the present invention. The amount of a resin compositionfor toners of the present invention is preferably from 50 to 95% byweight with respect to the whole weight of toner.

Components exclusive of a resin composition for toners will be describedin the following.

First, for colorants, previously known dyes and pigments can be used,more particularly including Carbon Black, Magnetite, PhthalocyanineBlue, Peacock Blue, Permanent Red, Lake Red, Rhodamine Lake, HansaYellow, Permanent Yellow, Benzidine Yellow, Nigrosine Die (C.I. No.50415), Aniline Blue (C.I. No. 50405), Chalco Oil Blue (C.I. No.azoecBlue 3), Chrome Yellow (C.I. No. 14090), Ultramarine Blue (C.I. No.77103), Dupont Oil Red (C.I. No. 26105), Orient Oil Red #330 (C.I. No.60505), Quinoline Yellow (C.I. No. 47005), Methylene Blue Chloride (C.I.No. 52015), Phthalocyanine Blue (C.I. No. 74160), Malachite GreenOcthalate (C.I. No. 42000), Lamb Black (C.I. No. 77266), Rose Bengal(C.I. No. 45435), Oil Black and Azo Oil Black. The amount of additionthereof is preferably from 3 to 15 parts by weight with respect to 100parts by weight of a resin composition for toners.

In addition, as charge control agents can be selected and used, asnecessary, well-known charge control agents including nigrosine,quaternary ammonium salts and azo dyes containing metals and the amountof use thereof is normally from 0.1 to 10 parts by weight with respectto 100 parts by weight of a resin composition for toners.

As for surface treatment agent, addition of the surface treatment agentto a toner can improve particle flowability of a developer and furtherimprove the life of the developer due to the fact that the surfacetreatment is present between the toner and the carrier or between thetoners. Illustrative examples include fine particles such as colloidalsilica, alumina, titanium oxide, polytetrafluoroethylene, polyvinylidenechloride, polymethyl methacrylate, polystyrene ultrafine particles andsilicones, and include, as commercial products, AEROSIL's 130; 200,200V, 200CF, 200FAD, 300, 300CF, 380, R972, R972V, R972CF, R974, R976,RX200, R200, R202, R805, R812, R812S, TT600, MOX80, MOX170, COK84,titanium oxide T805, titanium oxide P25 (up to here, available fromNippon Aerosil Co., Ltd. and Daicel-Degussa Co., Ltd.), CAB-O-SIL's L90,LM130, LM150, M5, PTG, MS55, H5, HS5, LM150D, M7D, MS75D, TS720, TS610and TS530 (up to here, available from CABOT Corp.), and particularly,for the surface area of the surface treatment agent, the specific areaas measured using the BET method by nitrogen adsorption is desirably 30m²/g or larger and more desirably from 50 to 400 m²/g. The amount ofsurface treatment agent added is preferably 0.1 to 20 parts by weightwith respect to 100 parts by weight of a resin composition for toners.

A toner of the present invention may contain a polyolefin wax and theamount thereof is from 0 to 10 parts by weight with respect to 100 partsby weight of a resin composition for toners.

The method of manufacturing a toner containing these materials of thepresent invention includes sufficiently mixing a resin composition fortoners of the present invention, a colorant and, if necessary, otheradditives by means of a powder mixer, subsequently fusing and mixing themixture by a kneading machine such as a heating roll, a kneader, or anextruder to sufficiently mix each component, subjecting the resultingmixture to cooling, followed by pulverizing and classifying, thennormally collecting the particles of from 8 to 20 μm and coating theparticles with a surface treatment agent by the powder mixing process toobtain a toner.

To a toner of the present invention can also be added a wax compositionat the initial stage of powder mixing in the step of manufacturing thetoner. The ratio by weight of ethylene polymer (copolymer) to waxcomposition (ethylene polymer (copolymer): wax composition) is from99.95 to 85.0: from 0.05 to 15.0.

A toner obtained by the present invention can be used for a variety ofdeveloping processes such as the cascade developing process, themagnetic brush process, the powder cloud process and the touchdowndeveloping process, the so-called microtoning process, which uses as acarrier a magnetic toner produced by the pulverizing method, and theso-called bipolar/magnetic toner process, in which necessary tonercharge is acquired by friction charging between magnetic toners;however, the applications thereof are not limited to these processes.

In addition, a toner obtained by the present invention can be used forvarious fixing processes such as the so-called oil-less fusing andoil-applying heat roll processes, the flash fusing process, the ovenfixing process and the pressure fixing process.

Further, a toner of the present invention can be used for differentkinds of cleaning processes such as the so-called fur brush process andthe blade cleaning process.

Detailed descriptions of the present invention will be given usingexamples in the following; however, the present invention is not limitedto these examples. Additionally, hereinafter, “parts” is defined as % byweight, unless otherwise indicated.

The molecular weights and molecular weight distributions of a styrenecopolymer and a polyester polymer were evaluated by GPC. Measurement wascarried out using a commercially available monodisperse standardpolystyrene as a reference under the following conditions.

Detector: SHODEX RI-71S

Solvent: Tetrahydrofuran

Column: KF-G+KF-807L×3+KF800D

Flow rate: 1.0 mL/min

Sample: 0.25% THF solution

Reliability of the measurement was confirmed on the ground that theMw/Mn of the NBS706 polystyrene sample (Mw=288,000, Mn=137,000,Mw/Mn=2.11) as measured under the aforementioned conditions is 2.11±0.1.

Melting points were determined by evaluating the peak values of waxendotherm by a DSC. The measurement was conducted by firstly raising thetemperature to 205° C. and rapidly decreasing it and then raising thetemperature from −20° C. to 200° C. at a rate of 10° C./min, usingSSC-5200 (Seiko Instruments Inc.).

The method of evaluating toners in these examples will be described inthe following.

{circle around (1)} Fixation Properties

An unfixed image was prepared with a copier made by modifying acommercial electrophotographic copier and then this unfixed image wasfixed using a heat roller fixing apparatus made by modifying the fixingpart of a commercial copier. The fixing speed of the heat roller was setat 210 mm/sec and the temperature of the heat roller was made varied by5° C. for the fixation of the toner. The fixed image thus obtained wasrubbed 10 times with a sand eraser (Tombow Pencil Co., Ltd.) under aload of 0.5 Kg. The image concentrations before and after this frictiontest were measured with a Macbeth reflection densitometer. The lowestfixing temperature when the rate of change in an image concentration ateach temperature became 70% or more was regarded as the lowest fixingtemperature. Further, the heat roller fixing apparatus used in this caseis not equipped with a silicone oil supplying mechanism. Additionally,the measurement was conducted at ambient temperature at normal pressure(temperature 22° C., relative humidity 55%).

Evaluation Results

∘: Lowest fixing temperature≦170° C.

Δ: 190° C.≧lowest fixing temperature>170° C.

X: Lowest fixing temperature>190° C.

{circle around (2)} Offfset Resistance Properties

The evaluation of offset resistance properties is based on theaforementioned measurement of the lowest fixing temperature. Theoperation of preparing an unfixed image using the aforementioned copier,subjecting the transferred toner image to fixing treatment by theaforementioned heat roller fixing apparatus and subsequentlytransporting a blank sheet of a transfer paper to the heat roller fixingapparatus under similar conditions to visually observe whether or nottoner spots are generated on the transfer paper, was repeated under acondition in which the setting temperature of the heat roller of theaforementioned heat roller fixing apparatus was made to increase one byone; as a result, the lowest setting temperature at which a spot due tothe toner was generated was regarded as the offset generationtemperature. In addition, the experiment was conducted at ambienttemperature at normal pressure (temperature 22° C., relative humidity55%).

∘: Offset generation temperature≧240° C.

Δ: 240° C.>offset generation temperature≧220° C.

X: 220° C.>offset generation temperature

{circle around (3)} Blocking Resistance Properties(preservingProperties)

After a sample was allowed to stand for 48 hours at a temperature of 55°C. and a relative humidity of 50%, 5g of the sample was put on a sieveof mesh 150 and was vibrated for 1 minute using a powder tester with thedial of the rheostat set at 3 (Hosokawa Powders Engineering Inst.). Theweight left on the sieve of mesh 150 after the agitation was measured toevaluate the residual weight ratio.

∘: Less than 20%

Δ: 20% or more and 35% or less

X: more than 35%

Methods of preparing samples provided for evaluation will be describedin the following. In addition, all waxes used were commerciallyavailable ones.

Wax Composition Preparation 1

Into a mixing vessel were fed 99.95 parts of Fisher-Tropsch wax with amelting point of 95° C. and 0.05 parts of an ethylene polymer (Mirason,available from Mitsui Chemicals Inc.) with a melt index of 3.3, togetherwith a small amount of solvent, and then the material was mixed withheating and agitating to obtain Wax Composition A.

Wax Composition Preparation 2

Wax Composition B was obtained by a method as in Wax Compositionpreparation 1, except that the amount of an ethylene polymer was 3parts.

Wax Composition Preparation 3

Wax Composition C was obtained by a method as in Wax CompositionPreparation 1, except that the amount of an ethylene polymer was 10parts.

Wax Composition Preparation 4

Wax Composition D was obtained by a method as in Wax CompositionPreparation 1, except that an ethylene polymer with a melt index of 70(Mirason, available from Mitsui Chemicals Inc.) was utilized.

Wax Composition Preparation 5

Into a mixing vessel were fed 99.90 parts of Fisher-Tropsch wax with amelting point of 95° C., 0.05 parts of an ethylene polymer (Mirason,available from Mitsui Chemicals Inc.) with a melt index of 3.3 and 0.05parts of a polyethylene wax (Hi-wax 220P, available from MitsuiChemicals Inc.), together with a small amount of solvent, and then thematerial was mixed with heating and agitating to obtain Wax CompositionE.

Wax Composition Preparation 6

Into a mixing vessel were fed 99.95 parts of a paraffin wax with amelting point of 73° C. and 0.05 parts of an ethylene polymer (Mirason,available from Mitsui Chemicals Inc.) with a melt index of 3.3, togetherwith a small amount of solvent, and then the material was mixed withheating and agitating to obtain Wax Composition F.

In addition, the Fisher-Tropsch wax and the paraffin wax used in WaxComposition Preparation 1 to 6 are designated as Wax G and Wax H,respectively.

Table 1 shows the composition and properties of wax compositionsobtained in the aforementioned Wax Composition Preparation 1 to 6 andWax Composition G and H.

Resin Preparation 1

Into a flask, the air-inside was replaced with nitrogen, were placed70.0 parts of a styrene monomer and 30.0 parts of n-butyl acrylate andthe mixture was heated and kept at 120° C. in an oil bath to polymerizethem for 4 hours by bulk polymerization. The polymerization conversionwas 32%. Then, to the material was added 120 parts of xylene and to thismixture was continuously added over 10 hours a mixture, as prepared bymixing and dissolving in advance, of 1 part of azobisisobutyronitrile(AIBN) and 80 parts of xylene while keeping the temperature inside theflask at 100° C. and subsequently the material was allowed to react for2 hours for polymerization completion to thereby obtain a high molecularweight polymer solution of Mn 18,000 and Mw 410,000.

Next, 80 parts of styrene and 20 parts of butyl methacrylate wererefluxed for polymerization in the presence of a solvent of xylene using4 parts of AIBN as a polymerization initiator to thereby obtain asolution of a low molecular weight polymer of Mw 3,200 and Mw/Mn 2.1.The maximum value is given in Table 2.

These two solutions were mixed in a ratio by solid component weight of 1to 1 and subsequently the solvent thereof was removed at 190° C. at 3torr of vacuum for 1 hour to obtain the target styrene copolymer. Thecopolymer thus obtained has an Mw of 210,000, an Mw/Mn of 65 and a Tg of60° C.

Resin Preparation 2 to 13

A low molecular weight polymer and a high molecular weight polymerhaving a similar composition as in Resin Preparation 1 were obtained bya method as in Resin Preparation 1, except that the amount of polymerinitiator, the polymerization temperature and the ratio of solvent werechanged and subsequently solutions of these polymers were mixed with anappropriate ratio and solvent was removed as in Resin Preparation 1 toobtain a styrene copolymer.

Resin Preparation 14

Into a four-necked flask fitted with a reflux condenser, a waterseparation device, a nitrogen gas-introducing tube, a thermometer and anagitating device were placed 65 parts of Polyol KB300 (Mitsui ChemicalsInc.), 30 parts of isophthalic acid, 5 parts of benzoic acid and0.05parts of dibutyltin oxide and then dehydration condensationpolymerization was carried out at 240° C. while introducing nitrogeninto the flask. When the acid value of the reaction product reached aspecified value, the product was taken out of the flask and was cooledand pulverized to thereby obtain Polyester Polymer (a).

Next, Polyester Polymer (b) was obtained by a method similar-to theaforementioned one, except that 31 parts of Polyol KB300 (MitsuiChemicals Inc.), 22 parts of diethyleneglycol (DEG), 3 parts oftrimethylolpropane (TMP) and 44 parts of isophthalic acid were fed.

Further, 60 parts of Polyester Polymer (a), 4 parts of Polyester Polymer(b) and 2 parts of tolylene diisocyanate was kneaded in a twin extruderat 180° C. to obtain a polyester polymer.

Table 2 tabulates properties of the resins obtained in Resin Preparation1 to 14.

EXAMPLE 1

A resin composition for toners was obtained by an operation similar toResin Preparation 1, except that 3 parts of Wax Composition A was addedin the step of solvent removal.

Further, after 87 parts of a resin composition for toners, 8.0 parts ofcarbon black (MA100, available from Mitsubishi Chemicals Corp.), 1.0part of a charge control agent (BONTRON S-34, available from OrientChemical Industries Co., Ltd.) and 3.0 parts of a polypropylene wax(Hiwax NP105, Mitsui Chemicals Inc.) were preliminary mixed with aHenschel mixer, the resultant mixture was kneaded by a twin extruder at120° C. and then was subjected to cooling, grinding and pulverizing,followed by classification by a classifier to thereby obtain a toner offrom 6.0 to 18.0 μm. After that, hydrophobic silica (R-972, availablefrom Aerosil Corp.) was added from the outside so that the ratio was 0.5parts by weight with respect to 100 parts by weight of theaforementioned toner and then the material was mixed by a Henschel mixerto obtain a toner. The evaluation results of the toner thus obtained aregiven in Table 3.

EXAMPLES 2 TO 18 AND REFERENCE EXAMPLES 1 TO 6

A toner was obtained by a method similar to the one in Example 1, exceptthat the kind of resin and the kind and amount of an added waxcomposition were changed. The evaluation results of the toners thusobtained are shown in Table 3.

EXAMPLE 19

The same operation as in the case of Example 1 was conducted and 3 partsof Hiwax NP105 was added in the step of solvent removal and subsequentlythe solvent was removed as in the case of Resin Preparation 1 for Tonersto thereby obtain a resin composition for toners. Then, the operationbased on Example 1 was conducted with this resin composition for tonersto obtain a toner. The evaluation results of the toner thus obtained aregiven in Table 3.

EXAMPLE 20

The same operation as in the case of Example 1 was conducted withoutadding polypropylene wax during kneading to obtain a toner. Theevaluation results of the toner thus obtained are given in Table 3.

EXAMPLE 21

A resin composition for toners was obtained by an operation similar tothat of Example 14 of Preparing Resin, except that 5 parts of WaxComposition A was added during the condensation polymerization ofPolyester Polymer (a). Then, a toner was obtained by a method similar tothe case in Example 1. The evaluation results of the toner thus obtainedare shown in Table 3.

TABLE 1 Wax (1) Wax (2) Melting Melt Fisher- Poly point of index ofTropsch Paraffin ethylene Ethylene Wax (1) ethylene wax wax Wax polymer(° C.) polymer Wax 99.95 0.05 95 3.3 Composition A Wax 97 3 95 3.3Composition B Wax 90 10 95 3.3 Composition C Wax 99.95 0.05 95 70Composition D Wax 99.90 0.05 0.05 95 3.3 Composition E Wax 99.95 0.05 733.3 Composition F Wax 100 95 Composition G Wax 100 95 Composition H

TABLE 2 Peak of Peak of Mw Mw/Mn M.W. (1) M.W. (2) Tg (° C.) A-1 210,00065 340,000 4,000 60 A-2 130,000 49 300,000 4,000 59 A-3 310,000 91300,000 4,000 61 A-4 230,000 78 290,000 4,000 52 A-5  11,000 30 190,0005,000 71 A-6 220,000 63 330,000 4,000 43 A-7 210,000 64 350,000 4,000 78A-8 110,000 4 120,000 — 60 A-9 370,000 110 310,000 4,000 60 A-10  90,00025 180,000 5,000 61 A-11 190,000 95 330,000 2,000 61 A-12 210,000 26320,000 13,000  59 A-13 110,000 30  90,000 4,000 58 A-14  18,000 12 5,400 — 58

TABLE 3 Composition of resin composition for toner Toner evaluationresults Content Preser- Wax of wax Fixation Offset vation Co- compo-compo- proper- proper- proper- polymer sition sition ties ties tiesExample 1 A-1 A 3 wt % ◯ ◯ ◯ Example 2 A-1 A 10 wt %  ◯ ◯ ◯ Example 3A-1 B 3 wt % ◯ ◯ ◯ Example 4 A-1 D 3 wt % ◯ ◯ ◯ Example 5 A-1 E 3 wt % ◯◯ ◯ Example 6 A-1 F 3 wt % ◯ ◯ ◯ Example 7 A-2 A 3 wt % ◯ ◯ ◯ Example 8A-3 A 3 wt % ◯ ◯ ◯ Example 9 A-4 A 3 wt % ◯ ◯ ◯ Example 10 A-5 A 3 wt %◯ ◯ ◯ Example 11 A-6 A 3 wt % ◯ ◯ Δ Example 12 A-7 A 3 wt % Δ ◯ ◯Example 13 A-8 A 3 wt % Δ Δ ◯ Example 14 A-9 A 3 wt % Δ ◯ ◯ Example 15A-10 A 3 wt % Δ Δ ◯ Example 16 A-11 A 3 wt % Δ Δ ◯ Example 17 A-12 A 3wt % Δ ◯ ◯ Example 18 A-13 A 3 wt % Δ Δ ◯ Example 19 A-1 A 3 wt % ◯ ◯ ◯Example 20 A-1 A 3 wt % ◯ ◯ ◯ Example 21 A-14 A 3 wt % ◯ ◯ ◯ ReferenceA-1 — — X X ◯ Example 1 Reference A-1 G 3 wt % Δ X ◯ Example 2 ReferenceA-1 H 3 wt % Δ X ◯ Example 3 Reference A-1 C 3 wt % Δ ◯ Δ Example 4Reference A-1 A 20 wt %  ◯ ◯ Δ Example 5 Reference A-14 — — Δ Δ ◯Example 6

What is claim is:
 1. A resin composition for toners comprising: (A) awax composition comprising an ethylene polymer having a melt index valueof from 0.1 to 100 as measured at 190±0.4° C. and a paraffin wax havinga melting point of from 70° C. to 120° C. or a Fisher-Tropsch wax havinga melting point of from 70° C. to 120° C.; and (B) a binder resin fortoners.
 2. The resin composition for toners according to claim 1,wherein with respect to a whole resin composition for toners, a contentof the (A) component is from 0.05% by weight to 15.0% by weight, and acontent of the (B) component is from 85.0% by weight to 99.95% byweight; and with respect to a whole (A) component, a content of theethylene polymer is from 0.01% by weight to 5.0% by weight, and a totalcontent of the paraffin wax and the Fisher-Tropsch wax is from 95.0% byweight to 99.99% by weight.
 3. The resin composition for tonersaccording to claim 1, wherein said binder resin is a styrene polymer(copolymer).
 4. The resin composition for toners according to claim 1,wherein said styrene polymer (copolymer) contains a constituent derivedfrom a styrene monomer and a constituent derived from a (meth)acrylatemonomer or a (meth)acrylic acid monomer; the styrene polymer (copolymer)has a glass transition temperature Tg of from 45° C. to 75° C.; and in achromatogram as measured by GPC, the styrene polymer (copolymer) has aweight-average molecular weight (Mw) of 100,000 or higher, has at leastone maximum value or one shoulder in both a molecular weight range offrom 3,000 to 12,000 and a molecular weight range of 100,000 or higher,and has a ratio (Mw/Mn) of Mw to number average molecular weight (Mn) offrom 15 to
 100. 5. The resin composition for toners according to claim1, wherein said binder resin for toners is a polyester copolymer.
 6. Theresin composition for toners according to claim 5, wherein saidpolyester copolymer has a glass transition temperature Tg of from 45° C.to 75° C.; and in a chromatogram as measured by GPC, the polyestercopolymer has an Mw of from 6,000 to 150,000, has at least one maximumvalve or one shoulder in the molecular weight range of from 3,000 to12,000, and has an Mw/Mn of 5 or more.
 7. The resin composition fortoners according to claim 1, wherein the resin composition for tonersfurther includes a polyolefin wax.
 8. A toner comprising the resincomposition for toners according to claim 1.